Wang Geng, Wang Qiang, Lu Wu, Li Jinghong
Department of Chemistry, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology, Tsinghua University, Beijing 100084, China.
J Phys Chem B. 2006 Nov 2;110(43):22029-34. doi: 10.1021/jp064630k.
One-dimensional (1-D) TiO2-B nanowires have been synthesized via a facile solvothermal route. The morphology and crystalline structures of the nanowires were characterized by using powder X-ray diffraction, low/high-resolution transmission electron microscopy, and Brunauer-Emmett-Teller methods. It is important with the calcination treatment at 350 degrees C to maintain 1-D morphologies of the material in the form of single-crystalline TiO2-B nanowires. In addition, a simple method was used to study the photogenerated charge transfer and photoelectrochemical properties of the TiO2-B nanowires in comparison with commercial TiO2 P25 nanoparticles based on the experimental data from the electric field-effected photocurrent action spectrum and Mott-Schottky measurements. It was revealed that TiO2-B nanostructures played an important role in the photoelectrochemical processes. The synthetic TiO2-B nanowire electrode exhibited unique electronic properties, e.g., favorable charge-transfer ability, negative-shifted appearing flat-band potential, existence of abundant surface states or oxygen vacancies, and high-level dopant density. Moreover, the obtained TiO2-B nanowires were found to display excellent humidity sensing abilities as functional materials in the humidity sensor application. With relative humidity increased from 5% to 95%, about one and half orders of magnitude change in resistance was observed in the TiO2-B nanowire-based surface-type humidity sensors.
一维（1-D）TiO₂-B纳米线已通过简便的溶剂热法合成。通过粉末X射线衍射、低/高分辨率透射电子显微镜和布鲁诺尔-埃米特-泰勒方法对纳米线的形态和晶体结构进行了表征。在350℃下进行煅烧处理对于保持材料呈单晶TiO₂-B纳米线形式的一维形态很重要。此外，基于电场效应光电流作用谱和莫特-肖特基测量的实验数据，采用一种简单的方法研究了TiO₂-B纳米线与商用TiO₂ P25纳米颗粒相比的光生电荷转移和光电化学性质。结果表明，TiO₂-B纳米结构在光电化学过程中起着重要作用。合成的TiO₂-B纳米线电极表现出独特的电子性质，例如良好的电荷转移能力、负移的平带电位、丰富的表面态或氧空位的存在以及高水平的掺杂剂密度。此外，发现所获得的TiO₂-B纳米线作为功能材料在湿度传感器应用中表现出优异的湿度传感能力。在基于TiO₂-B纳米线的表面型湿度传感器中，随着相对湿度从5%增加到95%，观察到电阻变化约一个半数量级。
